1. Field of the Invention
The present invention relates to communication between a television camera lens or other optical accessories for television shooting and a camera or other optical devices.
2. Related Background Art
In a conventional television broadcasting system, communication is performed with an analog signal as an camera-lens interface. For example, a lens system is controlled by designating to a lens a voltage for determining a position of focus lens or IRIS or determining a zoom lens speed. Conversely, lens information is transmitted by sending to a camera side a voltage indicating the position of focus lens, zoom lens or IRIS. On the other hand, in the lens, a feedback system using a potentiometer as a position sensor is constituted to form an analog servo control system.
In this case, in a conventional electric television lens and camera interface, one connector pin is allocated to each function. Specifically, for example, an iris control signal for controlling a television lens diaphragm from the television camera uses a fifth pin of a 12-pin connector between television lens and camera.
FIG. 35 is a block diagram of a conventional electric interface of television lens and camera.
A TV lens 5001 and TV camera 5002 are electrically connected via a connector 5003. When the electric interface is viewed from TV camera 5002, a switch input signal 5004 from a switch (not shown) in TV camera 5002 and an analog input signal 5005 generated by TV camera 5002 are transmitted to TV lens 5001. The TV lens 5001 transmits an analog output signal 5006 and a switch output signal 5007 to TV camera 5002.
An inside of TV lens 5001 will be described.
The switch input signal 5004 is connected to a signal processing circuit 5011 via a buffer 5008 in the TV lens 5001 to operate a function in the TV lens.
The analog input signal 5005 is transmitted to the signal processing circuit 5011 via an amplifier 5009. The analog input signal operates each function of TV lens 5001 such as an iris, zoom, focus, extender and the like (not shown). A motor 5013 for each function is operated via a motor driving circuit 5012 in response to a signal from the signal processing circuit 5011. Information indicating each function state of TV lens 5001 is obtained from a potentiometer 5014 operatively connected to the motor 5013, and transmitted as the analog output signal 5006 to the TV camera 5002 from the signal processing circuit 5011 via an amplifier 5010. Information of switch (SW) 5015 in the TV lens 5001 is transmitted as the switch output signal 5007 to the TV camera 5002.
Additionally, in the recent TV broadcasting, TV images clearer than before have been demanded, and not only the conventional items of TV camera-lens interface but also, for example, detailed lens information items need to be transmitted to the TV camera.
However, since no vacant connector pin is present between TV lens and camera, the conventional electric TV camera-lens interface cannot meet these demands.
Moreover, even if TV lens and camera using a new electric interface are provided from now on, they need to be combined for use with the conventional type TV lens and camera presently owned by a user.
According to one aspect of the present invention, there is provided a photographing system and an optical device. In the photographing system a serial communication of a request command and information is performed between a first device constituting the photographing system and a second device electrically connected to the first device, and the information is serially transmitted to the first device from the second device based on the request command from the first device. The second device is provided with a signal generating section for forming a signal independent of the request command, and the signal from the signal generating section is transmitted to the first device via a communication line provided independent of the serial communication. Thereby, various information items are transmitted in the serial communication without increasing the number of terminals. Additionally, when the information is transmitted at a high speed, the information is transmitted at a high speed via the communication line independent of the serial communication.
According to another aspect of the present invention, there is provided a photographing system and an optical device. In the photographing system a serial communication of a request command and information is performed between a first device constituting the photographing system and a second device electrically connected to the first device, and the information is serially transmitted to the first device from the second device based on the request command from the first device. The second device is provided with a signal generating section for forming a signal independent of the request command, and predetermined information is transmitted to the first device by the signal from the signal generating section via the serial communication independent of the request command from the first device. Thereby, various information items are transmitted in the serial communication, and when high-speed communication is necessary, the information is transmitted to the first device from the second device in the serial communication without transmitting the request command.
Further aspect of the present invention provides a lens device provided with a plurality of terminals, and a parallel communicator for transmitting or receiving information with a photographing device via each of at least some terminals for use among the plurality of terminals. The lens device comprises a serial communicator in which a plurality of information items are transmitted to the photographing device or received from the photographing device by digital signals via at least one terminal of the plurality of terminals, so that communication of various information items is performed.
Other objects of the present invention are clarified by embodiments described hereinafter with reference to the drawings.